Drain current testing of field effect transistors (FETs) is known in the art. Such drain current testing (or IDDQ testing) is performed by applying a power supply or drain-to-source voltage to a FET device. An excitation voltage is then imposed across the device from an input, such as the gate, to an output, and it is determined whether the quiescent or long-term drain-to-source current from the power source changes over time. If a defect exists, then the drain-to-source current will increase when the defect breakdown occurs.
Although such IDDQ testing can detect certain defects, other defects might not be detected in a commercially practical period of time by such testing. Thus, devices can pass IDDQ testing and can still fail in service due to defects. When failures occur in service, retrofitting or replacement of systems and components may be required. The cost of such retrofitting may greatly exceed the original price of the component.